Salmonella enteritidis PT4 infection in specific pathogen free hens: influence of infecting dose.

The period during which specific pathogen free hens, infected by direct introduction into the crop of either 10(3), 10(6) or 10(8) cells of Salmonella enteritidis PT4, excreted the organism in faeces was closely related to the size of the inoculum, with the birds excreting for mean periods of 3.4, 16.4 and 36.8 days, respectively. The production of either IgG or IgM was also dose related with the birds which received 10(3) cells having lower antibody levels than those in the other two groups. In contrast, there was no relationship between the contamination of egg contents and either antibody status, faecal excretion, or the dose administered.